Preparation of a stabilized cream product



Patented Apr. 11, 1950 PREPARATION OF A STABILIZED CREAM PRODUCT LewisH. Chrysler and Emory F. Almy, Columbus, Ohio, assignors to M & RDietetic Laboratories, Inc., a corporation of Ohio No Drawing.Application November 2, 1946, Serial No. 707,530. In Canada April 12,1946 27 Claims.

This invention relates to heat and acid stable milk products such asskim milk, whole milk and cream in liquid or dry form, and to themethods of making the same. In its more limited aspect it relates to acereal, Whipping or coffee cream, particularly the latter, having aprotein content of greatly increased stability to heat and/or acids, andto the method of making the same. The invention will be described withparticular reference to dried cream and to the method of making thesame, for illustrative purposes, but it is to be understood that it isapplicable to the preparation of other milk products mentioned herein.

This application is a continuation-in-part of our prior copendingapplication, Serial No. 599,514, filed June 14, 1945, now abandoned.

The treated dried creams of the present invention are stable and can bereconstituted readily to produce stable products. Either the dried creamproduct or the reconstituted product may be used to cream hot cofieewithout forming a heavy scum or feather on the surface. These creamproducts are characterized by having a low concentration of salts and aprotein content stable to heat and/or acids such as are encountered inhot coifee, strawberries, blackberries and the like, and in themanufacture of alimentary products such as creamed" tomato soup, processcheeses, mayonnaise, salad dressings, caramels, etc. Because of the lowsalt content our creams do not dampen the coffee bouquet and flavor, asis the case with reconstituted dried creams prepared in accordance withprior art methods.

A characteristic of the dried cream products of the present invention isthat they can be reconstituted in such relatively concentrated proportions as to possess whipping properties. Additionally, they can bereconstituted in more dilute proportions to give a rich tasting cerealcream or a rich cereal milk of about 8 to 10% butterfat content.

It is known that dried cream and reconstituted dried cream as ordinarilyprepared are not stable in brewed cofiee at the temperatures at which itis commonly served. Upon the addition of these prior art cream productsto hot coffee the cream breaks with the result that a part of itprecipitates to the bottom of the cup, some remains in suspension andsome forms a heavy scum or feather on the surface which is mingled witha considerable amount of freed butterfat or oil. Apart from theresulting unappetizing appearance, the cofiee is only slightly whitenedor creamed.

If the cream is homogenized prior to drying in accordance with prior artmethods the tendency of the reconstituted cream to oil-oil is reduced,

but the stability of the protein content of the cream in hot cofi'ee isnot improved and may actually be reduced by such treatment.

Stabilization of cream protein can be accomplished by converting thecasein to a soluble caseinate, usually a sodium caseinate, but thechemicals used in accomplishing this remain in the finished dried creamin the forms of salts which dampen the coffee bouquet and flavor. Whilesome of these oiiending salts may be eliminated by treating the milkproducts before drying with base exchange materials, others are added indoing so because the pH of the milk product to be treated with baseexchange material must first be adjusted with sodium hydroxide, andafter treatment with hydrochloric acid, citric acid or otheracids torestore the pH of the milk product. The overall effect of this baseexchange treatment of milk solids, including the subsequent acid pHadjustment step, is to build up the salt content of the final productand, consequently, to make more pronounced the flavor dampening effectthereof when used in hot cofiee.

In accordance with the present invention skim milk, whole milk or creamis subjected to a succession of treatments with ion-exchange materialsto reduce the salt content and at the same time stabilize the milkprotein to heat, thereby making possible the production of a dried creamproduct which can be added directly to hot brewed coffee or which canbereconstituted and then added to the hot coffee without affecting theflavor or bouquet of the coffee and without breaking or feathering. Inthis process alkalinity and acidity are preferably developed in the milkproduct solely by ion-exchange materials, and in no instance is the milkproduct subjected to such conditions of acidity as to effect coagulationof the lactalbumin, as is the case with the prior art methods. Inconsequence, the treated milk products of our invention retain thereadily dispersible lactalbumin as an added nutrient in the finishedproduct.

We are not prepared to state the precise reasons for the stability ofour cream products in hot coffee, but it appears that this stability islargely due to the presence in the cream of a milk solids not fatcontent having a markedly lower calcium content than normal milk solidsnot fat and, in particular, a markedly lower calcium (as Ca)tophosphorus (as P.) ratio in the milk solids not fat, which reductionin calcium and in the calcium to phosphorus ratio is brought about bythe treatment of the milk solids not fat with ion exchange materials. Ingeneral, the conditions for stability in hot coffee of the dried creamproduct of the present invention are more acoaaoc critical than for thereconstituted product. Thus, the dried cream product is stable on beingadded to hot brewed coffee when the calcium content of the milk solidsnot fat content of the cream is approximately 20 to 45% of the normalcalcium content of milk solids not fat and the calcium to phosphorusratio is in a range of from about 0.25 to about 0.55, preferably fromabout 0.35 to about 0.5. The reconstituted product (about 20% totalsolids, for example) is stable in hot coffee when the calcium content ofthe milk solids not fat is approximately 20 to 70% of normal and thecalcium to phosphorus ratio is in a range of from about 0.25 to about0.90.

As will be seen below, the normal calcium to phosphorus ratio of milksolids not fat is substantially in excess of about 1.2.

In the preparation of treated milk products in accordance with thepresent invention, particularly dried cream, it is preferred to treatmilk solids not fat in the form of skim milk and to supply the requiredbutterfat in the form of hightesting cream, or butter or butter oil at alater stage in the process prior to the drying step, for in the passageof whole milk or cream, particularly the latter, through theion-exchanger beds some butter-fat is retained in the beds, from whichit cannot be readily removed. Accordingly, the present invention will beillustrated by the treatment of skim milk to make a dried cream, but itis to be understood that the milk product subiected to treatment may bewhole milk or cream.

In carrying out the present invention, modified milk or milk solids areproduced by cation exchange of pasteurized skim milk of a pH of about6.5 to 6.9 acting in the sodium cycle. The exchange material employedmay be of the resin type such as are described, for example, inIndustrial and Engineering Chemistry, 1941, vol. 33, pages 697 et seq.and known as Amberlite resins; or of the carbonaceous or sulfonatedcarbonaceous type, or in some cases of the mineral or zeolitic type.Typical cation exchangers which may be employed are for example, thecommercial cation exchange materials such as Amberlite IR-IOO, ZeoKarb,Catex and the like. Exchange materials of the mineral or zeolitic type,for use in carrying out the present invention, require specialactivation or regeneration procedures to increase their effectiveness incation removal relative to anion removal.

In this treatment a substantial proportion, approximately 20 to 60 to70% and sometimes even more, of the calcium present in the skim milk isreplaced by sodium with the formation of a so dium caseinate in the skimmilk. The sodium caseinate, which is carried over into the final driedproduct, makes the product readily dispersible in water and hence easilyre-constituted, and more stable to the action of heat and acid such asare encountered in the case of hot coffee, for example. The skim milkduring this treatment becomes slightly alkaline, usually having a pH inthe order of about 7.50 to 8.0 or somewhat higher.

In the use of such cation exchangers as referred to above, regenerationis suitably effected by means of sodium chloride solution after prior 7treatment with alkali such as soda ash or sodium hydroxide, a wettingagent being preferably employed as set forth in the U. S. patent toHull, No. 2,346,844, granted April 18, 1944, where the exchange materialhas previously been used in the treatment of whole milk. Instead ofregenerating with sodium chloride solution. the regeneration may beeffected with a dilute solution of hydrochloric acid followed by asolution containing sodium chloride and a small proportion of sodiumhydroxide. After regeneration, or. if fresh, after an initial treatmentwith the sodium chloride solution, the exchange material is washed withwater until the sodium chloride content of the eiiluent is reducedpreferably to not more than 30 grains per gallon, at which time theexchange material may be used for the treatment of the skim milk or likemilk product used as the source of the modified milk solids. If desired,the skim milk may be slightly acidified to increase the effectiveness ofthe calcium removal.

The cation exchange treatment is so conducted as to reduce the ratio ofcalcium to phosphorus in the milk solids not fat of the treated skimmilk so that when it is blended with the desired amount of highbutterfat cream, butter or butter oil, the blend will have the reducedcalcium to phosphorus ratio referred to above. The reduction isaccompanied by an increase in pH, varying from about 7.0 to 7.25 as thelower limit to about 9.5 to 10.0 or even somewhat higher as the upper.The reduction is primarily in the calcium, the phosphorus being removedto a substantially less extent, only about 4 to 5%, in contradistinctionto the prior known treatments of milk fiuids with mineral baseexchangers in which both calcium and phosphorus are removed to asubstantial extent to reduce the curd tension of the milk.

Where the increase in pH is such that the pH of the. treated skim milkis in the order of about 7.5 to 8.0 and higher, it may be desirable toreduce this pH to a point within the range commonly found in fresh wholeor skim milk, say from about 6.5 to 6.90. This may be effected by theaddition of a suitable acid, such as hydrochloric acid, acetic acid,citric acid, or the like, or preferably by the use of cation exchangematerials of the types previously referred to, acting, however, in thehydrogen or acid cycle. Thus the exchange material employed, forexample, Amberlite IR-l00, is contacted with a dilute hydrochloric acidsolution for a considerable period of time, say 30 minutes, the acidsolution removed and the free acid washed out. This acid exchangematerial may then be agitated in suitable proportions with the treatedmilk to reduce the pH of the latter to the desired point. In this waythe reduction of the pH of the treated milk maybe effected withoutincreasing its salt content, as would be the case if acid were employedfor the purpose. Also, small additional amounts of calcium are usuallyremoved by this treatment.

Where the pH of the treated milk or skim milk is not excessive; say forexample Where it does not exceed about 7.5 to 8.0 or thereabout, it isnot necessary to apply to it the treatment with the acid exchangematerial to reduce its pH, and it, or the solids derived from it, may beemployed directly in the present process.

The substantially neutral skim milk from the bed of cation-exchangematerial operating in the hydrogen-cycle may be used in that form or itmay be dried and used in making alimentary products as described herein.In making dried cream, however, it is condensed to a total solidscontent of about 30 to 50%, the condensation being efiected under vacuumor at atmospheric pressure, as desired. The calculated amount of butter,butter oil or high butterfat fresh cream, say 35 to 55% cream, to getthe desired fat content in the finished cream powder, is added to thetreated skim milk either prior to or subsequent to the condensation, asdesired. Also if desired, part of the fat may be added to the treatedskim milk before condensation and the balance afterwards. The resultingmixture is heated to about 145 F. to 170 F. for about 15 to 20 minutes,then homogenized and finally dried, either by a spray or drum dryingapparatus, for example. The resulting product is a powder containing thedesired butterfat content, say a butterfat content of about 35 to 75%.The spray-drying procedure is preferred since it results in a fineporous powder which requires no grinding, and caramelization is avoided,but a drum dryer can be utilized with satisfactory results. Theresulting dry cream powder is suit-- able for use as such or in areconstituted form. If desired, the dried cream product may bevacuum-packed or packed in an inert gas for storage or transportation.

The final dried product, when used either in that state or in areliquefied state, possesses remarkable whitening or creamingproperties. For example, a 20% total solids solution of the cream powderin water will cream at least twice as much coffee as ordinary 27% totalsolids coffee cream and gives a full, rich cream flavor when added tohot or cold cereals. By increasing the reliquefied total solidsslightly, say to about 30 to 35%, the cream can also be whippedproducing a product of an unusually high yield and fine flavor.

In general, for the treatment of the milk, which may be whole or skimmilk, either raw or pasteurized, it is found that 1.25 to 1.50 cubicfeet of the exchange material to each 12 to 14 inches depth of bed foreach 30 gallons of milk to be processed is sufiicient when a pH of about8 is secured on the treated milk. More of the fluid milk may be treatedwith the same amount of exchange material, but the relative percentageof calcium removal on the total treated product will be lower and the pHwill move toward the acid side. A suitable rate of flow through the bedof exchange material is three minutes per gallon. Ordinarily a smallamount of the wash water remains in the exchange material and thiscauses a slight dilution of the treated milk.

After the exchange material has been prepared, the milk is passedthrough it at the rate above mentioned and in general, a calcium tophosphorus ratio of the treated milk of about 0.15 to 0.75 is secured.By using a larger proportion of exchange material based on the milktreated or by slightly acidifying the milk prior to treatment, suitablywith hydrochloric acid, lactic acid or citric acid, or by variouscombinations thereof, a higher relative proportion of the calcium may beremoved; or alternatively, if the same over all proportion of calciumremoval is desired, a larger amount of milk may be treated per cubicfoot of exchange material. Thus by preliminarily acidifying the milkbefore treatment with the exchange material, say to a pH of about 6.10or lower, a larger amount of milk, ranging from about 20 to about 45%greater, may be treated, per cubic foot of exchange material, securingvery closely the same calcium to phosphorus ratio in the treatedproduct. In carrying out the present invention the treatment with theexchange material is controlled to secure in the solids of the treatedwhole or skim milk a calcium to phosphorus ratio of from about 0.15 to0.75 and preferably from 0.25 to 0.6.

In a typical operation, using 1.36 cubic feet of the resinous cationexchange material Amberlite IR-100per 14 inch depth of bed to about eachgallons of milk treated, the fresh whole milk treated had a total solidscontent 01' 12.66%, a pH of 6.72 and a calcium to phosphorus ratio of1.155. After treatment, the treated product had a total solids contentof 10.22%, a pH of 7.43 and a calcium to phosphorus ratio of 0.547.

In another case, using a similar exchange ma-- terial, the fresh wholemilk had a pH of 6.67 and a calcium to phosphorus ratio of 1.137. Inthiscase the fresh milk was treated with citirc acid to bring itsacidity to 0.24% (calculated as lactic acid) and its pH to 6.08. It wasthen passed through the cation exchange material, the conditions beingsimilar to those of the preced ing example, except that in this caseapproximately 73 gallons of the milk were treated per 1.36 cubic feet ofthe exchange material. The pH of the product was 7.92 and the calcium tophosphorus ratio was 0.429.

If desired, the pH of the treated milk may be reduced after thetreatment with the cation exchange material, for example, by agitationwith cation exchange materials such as those previously described, inthe hydrogen cycle. The ex change material may be placed in the hydrogencycle by simple agitation with dilute acid, for example, dilutehydrochloric acid, and washing out the free acid.

As is readily apparent, by varying the relative proportion of the milkor skim milk treated per unit volume of the exchange material, thecalcium (as Ca) to phosphorus (as P) ratio in the final product may bevaried as desired.

In revivifying the exchange material after having been contacted withthe whole milk or skim milk, it may suitably be washed first with warmwater; then with a solution made alkaline with soda ash and containing awetting agent, such as those referred to in the patent to Hull, abovereferred to, and then again washed with warm water. It may then beregenerated as I heretofore described.

Where the milk under treatment has been skim milk, the wash with alkalisolution containing a wetting agent may be dispensed with. A suitablemethod of revivifying in such case is first to wash the exchangematerial with water; then with dilute hydrochloric acid in solution andagain with water until the wash water no longer has an acid taste. It isthen revivified by passing a slightly alkaline salt solution through thebed of exchange material, a suitable solution being one containing 0.5pound of sodium chloride and .013 pound of sodium hydroxide per gallon.The bed of exchange material is then washed until the sodium chloridecontent of the eiiiuent is reduced to not over 30 grains per gallon, aspointed out above.

The following examples are illustrative of our invention. In theseexamples the flow of skim milk through the ion exchanger beds was at therate of /3 gallon per minute per 1.36 cu. ft. of bed, unless otherwiseindicated.

Example 1 In preparing the cationic exchanger bed, Am-

berlite IR-IOO, for operation residual milk left in the bed from aprevious run'was washed out by passing water upfiow through the bed.This water was no longer acid to the taste. After draining of! the washwater 70 gallons of sodium chloride solution containing 500 grams ofsodium hydroxide were passed downfiow through the bed in order toconvert the exchanger to the sodium cycle. The bed was then washeddownflow with water in the usual manner and was then ready foroperation.

Pasteurized skim milk was then passed downpassed through the bed until30 gals. of skim milk efiluent having a composite pH of 8.92 wereobtained. After holding the treated skim milk for one hour the pH wasreduced to 6.79 by rapidly stirring in slightly over 8 quarts of IR-100acting in the hydrogen cycle.

180 lbs. of the adjusted treated skim milk were mixed with 43 lbs. offluid cream testing 43.53% butterfat. The mixture was forewarmed flowthrough the regenerated cationic exchanger 10 at 170 F. for minutes, 7minutes being reuntil gals. of treated skim milk eiiluent were quired tobring the temperature to 170 F. It obtained. The composite pH of thiseilluent was was then condensed in the small vacuum pan 9.01. Afterholding for one hour the pH of the to a condensing strike of 6.0 B. at130 F. 80 eflluent was adjusted to 6.80 by rapidly stirring lbs. of thecondensed product were obtained in the requisite quantity of IR,-100acting in the which was then homogenized at 2000 lbs. preshydrogencycle. sure and a temperature at 130 F. The homo- To 180 lbs. of thetreated skim milk were added genized product was then spray dried and ayield 43 lbs. of fluid cream testing 43.5% butterfat. of 29 lbs. ofdried cream was obtained. The mixture was forewarmed at 170 F. and heldThe data in the following table show the anaat that temperature for 20minutes, 15 minutes 2" lytical characteristics of the treated skim milkbeing required to bring the mixture to the temand of the dried creammade therefrom:

DH P i rcgnt lcFigint Pergini Pcgfnt Perlcent C811, Pggegitega Orig.skim 6.72 9.43 .774 .1247 .1037 1.203 Treated skim 8.92 8.53 .601 .0374.0976 0.383 611 Powder 6. 79 was 51.19 3.473 .2512 .5094 0.493 59 1 Thisis the moisture content of the dried product.

perature of 170 F. The mixture then was condensed in a small evaporatingpan until a condensing strike of 6.4 B. at 130 F. was obtained.

,The yield was approximately 76 lbs. of condensed product. The condensedproduct was then homogenized at 2000 lbs. pressure, the temperature ofhomogenization being approximately 130 F. and the product was spraydried.

The dried product had an excellent texture and was not greasy to thefeel when rubbed be- Example 3 The bed was prepared for operation in thesame manner as described in Example 1 with the exception that only 350grams of sodium hydroxide tween the thumb and forefinger of the hand.was added to the 5% sodium chloride solution in- Approximately 28 lbs.of dried cream were obstead of the 475 grams used previously.

tained from the driyer. The following table Pasteurized skim milk havinga pH of 6.68 was shows the analytical data of the treated skim passedthrough the exchanger bed until 30 ga s.

milk and of the dried cream made therefrom: of treated skim milk emuenthaving a pH of DH P clirlcgnt Pelrgeznt Pexgelnt Pecaent Percent Ca PPregggiega Orig. skim 9. 24 .149 .1222 .1011 1. 202

Treated skim 9.01 8.73 .622 .0319 .0967 0.392 m Powder 6.80 1.32 50.873.608 .2414 5174 0.467 61 This is the moisture content of the driedproduct.

Tests of the reconstituted cream (20% total solids) and of the driedcream in hot coffee showed that this batch of cream was soluble, did notbreak or coagulate and did not produce feathering.

Example 2 The cleaning and regenerating of the cationic exchanger bedwas carried out in the same manner as described in Example 1 with theexception that 4'75 grams, instead of 500 grams, of sodium hydroxidewere added to the 5% sodium chloride regenerating solution.

H Percent Percent Percent Percent Percent CB P Percent Ca P T. s. FatAsh Ca P removed Orig. skim 6. 68 9. 24 753 1377 1051 l. 310 Treatedskim 8. 09 8. 82 638 .0436 .0981 0. 444 66 Powder 6.75 1.42 49. 52 3.626.2704 .5330 0.507 61 1 This is the moisture content of the driedproduct.

Pasteurized skim milk having a pH of 6.72 was The reconstituted creamwas quite soluble and 9 perfectly stable in hot coffee showing noevidences of protein coagulation, feathering or oiling oil of the fat.This was also true when the cream in the dry form was added to hot asthe lower limit, because we have found that the stability of the treatedskim milk solids to heat and acid becomes reduced as the pH of the anioneiliuent approaches this lower limit. The

coffee at 180 F. temperature. treated skim milk solids are almostuniformly Example 4 stable to heat and acid when the anion eflluent ismaintained between a pH of about 9.0 to 10.6.

The cleaning and re nerating of the cationic Below these limits, to a pHof about 8.5, ocexchanger bed was carried out in the same mancasionalinstability of the treated skim milk solids ner as described in Example'1 with the excepresults. Below a pH of about 8.5 the treated tion that80 gals. of a 5% sodium chloride regenskim milk solids are usuallyunstable to heat erating solution free from alkali was used. and acid.

Pasteurized s m ilk havin a p o pprox- The alkaline skim milk is nowcontacted with imately 6.7 was passed through the bed until 30 a cationexchange material operating in the hygals. of skimmilk emuent having acomposite drogen cycle until the pH thereof is brought back pH of 7.83were obtained. This batch of milk to about 6.5 to 6.8. One of theabove-mentioned was adjusted to a pH of 10.0 by the addition of cationexchange materials which operate in the 80 ml. of 50% sodium hydroxidesolution. After hydrogen cycle may be used to restore the pH holding onehour, the pH was readjusted to 6.70 of the cation exchange treated andanion exby stirring in rapidly a quantity of 1R-100 acting changetreated skim milk. This material may be in t hydrogen cycle, in the formof a bed through which the treated To 180 lbs. of the filtered treatedskim milk, milk is passed, or the material may be mixed with 46 lbs. offluid cream containing 40% butterfat the treated milk in a suitabletank. During this was added and the whole was forewarmed,conacidification treatment of the skim milk excess densed, homogenized,and spray driedasdescribed sodium ions, in an amount suiiicient torender in Example 1. Approximately 27 lbs. of cream the skim milkpractically neutral, are removed. powder was obtained having thefollowing Small additional amounts of calcium are also analyticalcharacteristics. usually removed during this treatment.

pH P iiregnt Pelr gant Pi ggnt Peacaent Perlccnt CUP Pggg taga Orig.sklm0.1 9.24 .766 .1319 .1000 1.244 'Ireatedskim moo 8.18 .020 .0308 .10130.003 11. Powder 6.70 1.23 61.38 3.667 .2041 .02l2 0.501 to 1 This isthe moisture content of the dried product. i

The coflfee test showed that the reconstituted The following is anexample of the process 01 cream (20% total solids) and the dry creamwere 40 our invention for making a batch of powdered both quite solubleand stable in hot cofiee with coffee cream, using the additional anionexchange no pronounced feathering being evident. treatment to removeacid ions.

In some instances, where there is in the skim Exam Z6 5 milk a largeproportion of acid ions present as p salts, namely, potentialacid-forming ions present 2100 lbs. (250 gals.) of cold, pasteurizedskim in combination with cations assalts, particullarly milk having a pHof 6.78 were passed downilow phosphates and citrates, it may bedesirable to through a 6 cu. ft. bed of freshly revived cation. followthe initial cation exchange treatment of exchange material operating'inthe sodium cycle the skim milk with a treatment with an anion (ZeoKarb)at a flow rate of 10 gals, per 6 minutes. exchange material to removethe excess of such A fixed milk level was maintained on the bed ions.The removal of acid ions of these salts is and the cation exchangetreated milk was pumped particularly advantageous because the presencefrom the bottom discharge. of the. bed to the top of these salts in skimmilk is largely responsible of a 3 cu. ft. bed jof anion exchangematerial for the dampening of the coffee aroma and (DeAcidite) andpassed through the bed .at the flavor. same flow rate. The treatedvmilk, discharging Common anion exchange materials of this type from thebottom of the anion exchange bedwas are those known to the trade asDeAcidite, Anex, passed into a holding tank. Amberlite 1121-4, etc. Theabove two beds delivered approximately During the treatment of thecation-exchange gals. total of bed water before themi lk put inf treatedskim milk with the anion exchange'mateits appearance at the anionexchange'bed disrial the skim milk becomes alkaline, the pH there- 60charge and at that point the valve was switched of usually varying overa wide range, from about sending the treated milk to the holding tank.10.5 downwardly. If the skim milk is passed Since the beds were wet withrinse bed water through a bed of anion exchange material, either at thestart of the operation, a dilution of the downflow or upflow, as is theusual practice in milk passing through the beds took place, re thetreatment of milk products with such mate- 5 sulting in an increase ofapproximately 30gals. rial, the initial skim milk eilluent has a pH inover the original 250 gals. 1 the order of about 10.5 or somewhathigher. As The milk discharging from the cation exchange the activity ofthe bed to exchange ions diminishes bed had a pH of 7.62. The pH of themilk.dis-' on continued passage of the skim milk therecharging from theanion exchange bed at the through the pH of the skim milk eiiluentprogresbeginning of discharge, using the first 10 gals. sively decreasesdown to about 8.25 to 8.5 and for testing pH, had a pH of 10.44. Thenext below. We prefer to discontinue the contact of 10-gal. batch had apH of 10.43, the next 10.83, the skim milk with the anion exchangematerial the next 10.18 and the pH of the succeeding porwhen the pH ofthe skim milk passing from the tions of the milk tapered of! generally,and th bed is in the order of about 8.5, preferably 9,0, final 10-gal.batch had a pH of 8.87..

As soon as this pH adjustment was made, the agitation was stopped andthe ion exchange material was permitted to settle to the bottom of thetank with the present invention with dried cream produced commerciallyin accordance with prior art methods. The data submitted is on fivesamples of skim milk which came from the same original batch as did thecream used in all of the live samples. The skim milk of the aboveillustrative example also came from the same original batch of milk.

Sample; ControlAll untreated skim. No treated skim. 1 -No untreatedskim. All treated skim. 2 untreated skim, 85% treated skim. 3 untreatedskim. 70% treated skim. 4 --45% untreated skim. 55% treated skim.

Analytical data on the fluids, previous to condensing Percent Per centPer cent Ca Per cent Per cent P Per cent 58mph Lactose Cs. removed Premoved Protein DH Orig. Skim-alter pH adiust.... 4. 97 0.1185 0. i5563. 6. 7s 1 3. 8i 0. 0676 43. 1 D. 109 30. 6 3. 02 6. 00 2 4. 11 0. 075036. 6 0. 107 31. 4 3. 06 6. 80 3 4-21 0.0830 30. 2 0. 112 27. 9 3. 136.85 4 4. 44 0. 21. 8 0.116 25. 8 3. l9 6. 80

after which the pH-adiusted milk was drawn off through a filter orclarifier and pumped to the i'orewarming wells where it was heated to170 F., held 20 minutes and then drawn into the condenser and condensedto a -45% total solids content at a condensing temperature of 135 F.

The condensed material was then transferred to a tank and a sample wastaken from which the The samples were condensed to a. total .solidscontent varying progressively from 36% to 42.8%. The cream mixing,homogenizing and drying pro cedures were identical on all of the fivesamples and followed the procedure of the illustrative example. Theanalytical results on the finished powders and on commercial dried creamare as follows:

For For Per Per Per Per Cent Per Cent Per Cent Per Cent Per Cent sampeMoisture Ash Fat Protein Lactose Cent Gem Com Com Ca P 1 Na K Control 0.B3 13 04 18. 76 27. 80 O. 654 0. 5713 O. 412 0. 217 0. 640 1 1. 2 3. 563 19. 46 24. 45 i). 385 0. 5469 0. 399 0. 791 O. 006 2.- 0. 73 3.55 51.37 18. 76 24. 15 0. 308 0. 5315 O. 40 0. 730 ii. 101 0. 81 3- 74 9. 8413. 95 24. 85 0. 445 i). 5508 0. 445 O. 648 0. 188 4 0- 96 9- 93 13. 6625. 15 0. 498 0. 5466 U. 428 0. 530 i). 324

Comm'l dried cream 0. 66 to 2. 43 to 50v 00 to 11. 00 to 14.70 to SeeControl Sample per cent of total solids was determined. This was foundto be 176 lbs. in the illustrative example. 191 lbs. of butter-fat inthe form of 50% cream were added to the condensed treated skim milk andthe mixture was well mixed and then run through a homogenizer at 2000 p.s. i. and F.

From the homogenizer the cream was passed into a holding tank from whichit was pumped to the but this "feathering" was no worse than thatdespray drier and spray-dried, resulting in 382 lbs. of

finished cream powder containing 50% butterfat.

fThe untreated solids not fat which are carried along with the creaminto the condensed treated skim milk, in this as well as in the previousexamples,- have no eflect on the stability of the proteins oi! thefinished dried product. Where the pH oi the eilluent from the anionexchange bed is 9 and higher, substantial proportions of untreated milksolids not fat maybe added to the effluent from the final ion exchangetreatment without enacting the stability of the protein in the finalproduct to heat and acid. As the pH of the eiiluent from the anionexchange bed is up around the upper limit of about 10.5, larger amountsof untreated milk solids not fat can be added to the efliuent from thefinal ion exchange treatment without all'ecting the stability of thefinal product to heat and acid.

The following tabulated data is submitted to show theei'lects of the ionexchange treatments on the skim milk and to compare the productcomposition of dried cream produced in accordance veloped in coffee towhich fresh 20% cream was added. Sample 4 produced a slightly heavier.feathered film than sample 3, but there was no typical breaking andprecipitation as in the control sample.

The calcium tophosphorus ratio of the cream of sample 1 was 0.67; thatof sample 2 was 0.69; that of sample 3 was 0.81; and that of sample 4was 0.91.

The dried creams produced in accordance with the present invention, whenpackaged as desimilar commercially prepared products where curdling willtake place if fresh cream is added. In the dried cream product of thepresent invention the fat globules of the added butterfat are coatedwith the sodium caseinate produced by the hereinabove describeddemineralization process and this coating makes possible the productionof a liquid cream possessing much greater stability and ability to colorcoffee than is possible with a calcium easeinate as in fresh cream, andthis increased ability to color coffee carries through into the driedcream so successfully that the powder itself can be added directly tohot or boiling coffee without disturbing its coffeecoloring propertiesor its stability. In contrast to the dried creams of the presentinvention, dried fresh cream prepared in accordance with prior artmethods, whether homogenized or not, breaks or curdles when added to hotcoffee.

In addition to the foregoing, the creams of the present invention retainmost 01' the lactose and albumin which are lost in the acid curd processof making sodium caseinate. While it is conceivable that butterfatglobules can be coated with a sodium caseinate which is produced bytreating casein with sodium hydroxide and the resulting alkalinity ofthe product reduced to a pH of about 6.8 by adding hydrochloric, citric,phosphoric or like acid, such a product is not the product of thepresent invention, for there is such a high increase in the salt contentthereof as to make it practically useless for the purposes heretoforementioned.

In the examples given, whole milk may be used instead of the skim milkspecificallyreferred to, the proportion of cream employed being modifiedso that the final product has approximately the same fat content.

It is to be understood that the process described herein is not to belimited to the manufacture of a powdered cereal, whipping or coffeecream, for it can also be .used to produce whole milk or skim milkpowder or fluid which is particularly adapted for use in any processedfood where the stability of the milk used is endangered by thetemperature and/or acidity of the materials to which it may be added.For example, liquid or dried whole milk, skim milk or cream can be usedwithout fear of breaking or curdling in the making of high acid soupssuch as creamed tomato soup, for example, or in candy manufacture,particularly in overcoming the destabilization that takes place inordinary milk solids in caramel cooking or in the manufacture of processcheeses, or in the prevention of clotting or breaking of various typesof emulsions such as are encountered in the manufacture of mayonnaise,salad dressings and oleomargarine.

The present invention is not to be construed as limited to the detailsof the illustrative ex amples, for many variations in proportions,procedures and other details may be made without departing from thescope of the invention as set forth in the appended claims. Thus, forexample, the treated skim milk, prior to condensation, may be mixed withthe required amount of high butterfat content cream and the mixture thenforewarmed, condensed, homogenized and dried as described above. Thisprocedure makes it possible to give the cream the same forewarmingtreatment as the skim milk, thus destroying deleterious enzymes as wellas removing any undesirable volatile odors and flavors which areconducive to poor keeping qualities of the final products. If desired,the condensed, homogenized mixture of treated skim milk and cream may becanned or otherwise packaged while it is in the liquid state, eitherwith preliminary or subsequent sterilization, and the product used, asdesired, in liquid form, either with or without dilution. Othervariations will suggest themselves from the foregoing.

We claim:

1. A process for producing a milk material comprising treating a fluidmilk product having a substantially normal calcium and phosphoruscontent and a pH of about 6.5-6.8 with a cation exchange materialoperating in the sodium cycle, until the calcium content of the productis approximately 20 to of normal and there is secured in the product acalcium to phosphorus ratio of about 0.15 to 0.75, thereby raising thepH of the product, and treating the resulting product with a cationexchange material operating in the hydrogen cycle until the pH of theoriginal milk product is substantially restored.

2. A process for producing dry cream comprising treating skim milk andlike milk products having a substantially normal calcium and phosphoruscontent and a pH of about 6.5 to 6.8 with a cation exchange materialoperating in the sodium cycle, until the calcium content of the productis approximately 20 to 70% of normal and there is seeured in the producta calcium to phosphorus ratio of about 0.15 to 0.75, thereby raising thepH of the product, and treating the resulting product with a cationexchange material operating in the hydrogen cycle until the pH of theoriginal milk product is substantially restored, condensing the treatedproduct, adding an amount of .butterfat or butterfat-containingmaterialto the condensed treated product sufficient to give the desired fatcontent in the dried cream but not to increase the calcium to phosphorusratio beyond the range of about 0.25 to 0.90, homogenizing the mixtureand drying it.

3. A process for producing a dry cream comprising treating skim milk andlike milk products having a substantially normal calcium and phosphoruscontent and a pH of about 6.5 to 6.8 with a cation exchange materialoperating in the sodium cycle, until the calcium content of the productis approximately 20 to 70% of normal and there is secured in the producta calcium to phosphorus ratio of about 0.15 to 0.75, condensing thetreated product, adding an amount of butterfat or butterfat-containingmaterial to the condensed treated product sufficient to give the desiredfat content in the dried cream but not to increase the calcium 'tophosphorus ratio beyond th range of about 0.25 to 0.90, homogenizing themixture and drying it.

4. A process for producing a milk material comprising treating a fluidmilk product having a substantially normal calcium and phosphoruscontent and a pH of about 6.5 to 6.8 with a cation exchange materialoperating in the sodium cycle, until the calcium content of the productis approximately 20 to 70% of normal and there is secured in the producta calcium to phosphorus ratio of about 0.15 to 0.75, there-by raisingthe pH of the product, treating the resulting prodnet with an anionexchange material to remove acid ions present as salts and then with acation exchange material operating in the hydrogen cycle until the pH ofthe original milk product anoacec a substantially normal calcium andphosphorus content and a pH of about 6.5 to 6.8 with a cation exchangematerial operating in the sodium cycle, until the calcium content of theproduct is approximately 20 to 70% of normal and there is secured in theproduct a calcium to phosphorus ratio of about 0.15 to 0.75, therebyraising the pH of the product, treating the resulting product with ananion exchange material to remove acid ions present as salts and thenwith a cation exchange material operating in the hydrogen cycle untilthe pH of the original milk product is substantially restored, anddrying the treated product.

6. The process for producing a milk material set forth in claim 5wherein the treatment with anion exchange material is continued untilthe pH of the product is further raised to about 8.5 to 10.5. v

7. The process for producing a milk material set forth in claim 5wherein the treatment with anion exchange material is continued untilthe pH of the product is further raised to about 9.0 to 10.5.

8. A process for producing a milk material comprising treating a fluidmilk product having a substantially normal calcium and phosphoruscontent and a pH of about 6.5 to 6.8 with a cation exchange materialoperating in the sodium cycle, until the calcium content of the productis approximately 20 to 70% of normal and there is secured in the producta calcium to phosphorus ratio of about 0.15 to 0.75, thereby raising thepH of the product, treating the resulting product with an anion exchangematerial to remove acid ions until the pH of the product is furtherraised to about 9.0 to 10.5, and then with a cation ex-' change materialoperating in the hydrogen cycle until the pH 01 the original product issubstantially restored, and spray drying the treated product.

9. A process for producing dry cream comprising treating skim milkhaving a substantially normal calcium and phosphorus content and a pH ofabout 6.5 to 6.8 with a cation exchange material operating in the sodiumcycle, until the calcium content of the product is approximately 20 to70% of normal and there is secured in the product a calcium tophosphorus ratio of about 0.15 to 0.75, thereby raising the pH of theproduct, treating the resulting product with an anion exchange materialto remove acid ions present as salts and then with a cation exchangematerial operating in the hydrogen cycle until the pH of the originalmilk product is substantially restored, condensing the treated product,adding an amount of cream to the condensed treated product suilicient togive the desired fat content in the dried cream, but not to increase thecalcium to phosphorus ratio beyond the range of about 0.25 to 0.90,homogenizing the mixture and dryin it.

10. A process for producing dry cream comprising treating skim milkhaving a substantially normal calcium and phosphorus content and a pH ofabout 6.5 to 6.8 with a cation exchange material operating in the sodiumcycle, until the calcium content of the product is approximately 20 to70% of normal and there: is secured in the product a calcium tophosphorus ratio of about 0.14 to 0.75, thereby raising the pH of theproduct, treating the resulting product with an anion exchange materialto remove acid ions present as salts and then with a cation exchangematerial operating in the hydrogen cycle until the pH of Ill) theoriginal milk product is substantially restored, adding an amount ofcream to the treated product suflicient to give the desired fat contentin the dried cream, but not to increase the calcium to phosphorus ratiobeyond the range of about 0.25 to 0.90, and, successively, condensing,homogenizing and drying the mixture.

11. The process of producing dried cream set forth in claim 9 whereinthe treatment with anion exchange material is continued until the pH ofthe product is further raised to about 8.5 to 10.5.

'12. The process of producing dried cream set forth in claim 9.whereinthe treatment with anion exchange material is continued until the pH ofthe product is further raised to about 9.0 to 10.5.

13. The process of producing dried cream set forth in claim 10 whereinthe treatment with anion exchange material is continued until the pH ofthe product is further raised to about 9.0 to 10.5.

14. A process for producing dry cream comprising treating skim milkhaving a substantially normal calcium and phosphorus content and a pH ofabout 6.5 to 6.8 with a cation exchange material operating in the sodiumcycle, until the calcium content of the product is approximately 20 to70% of normal and there is secured in the product a calcium tophosphorus ratio of about 0.15 to 0.75, thereby raising the pH of theproduct, treatin the resulting product with an anion exchange materialto remove acid ions present as salts and then with a cation exchangematerial operating in the hydrogen cycle until the pH of the originalmilk product is substantially restored,

adding a relatively small amount of untreated skim milk to the treatedskim milk, condensing the mixture, adding an amount of cream to thecondensed mixture suificient to give the desired fat content in thedried cream, but not to increase the calcium to phosphorus ratio beyondthe range of about 0.25 to 0.90, homogenizing the mixture and drying it.

15. A process for producing a cream product comprising treating skimmilk and like milk products having a substantially normal calcium andphosphorus content and a pH of about 6.5 to 6.8 with a cation exchangematerial operating in the sodium cycle, until the calcium content of theproduct is approximately 20 to 70% of normal and there is secured in theproduct a calcium to phosphorus ratio of about 0.15 to 0.75, condensingthe treated product, adding an amount of butterfat orbutterfat-containing material to the condensed treated productsuflicient to give the desired fat content in the cream, but not toincrease the calcium to phosphorus ratio beyond the range of about 0.25to 0.90, and homogenizing the mixture.

16. A process for producing a cream product comprising treating skimmilk and like milk products having a substantially normal calcium andphosphorus content and a pH of about 6.5

- to 6.8 with a cation exchange material operating in the sodium cycle,until the calcium content of the product is approximately 20 to 70% ofnormal and there is secured in the product a calcium to phosphorus ratioof about 0.15 to 0.75, thereby raising the pH of the product, andtreating the resulting product with a cation exchange material operatingin the hydrogen cycle until the pH of the original milk product issubstantialy restored, condensing the treated product, adding an amountof butterfat or butterfat-containlng material to the condensed treatedproduct suflicient to give the desired fat content in the cream, but notto increase the calcium to phosphorus ratio beyond the range of about0.25 to 0.90, and homogenizing the mixture.

17. A process for producing dry cream comprising treating skim milk andlike milk products having a substantiall normal calcium and phosphoruscontent and a pH of about 6.5 to 6.8 with a cation exchange materialoperating in the sodium cycle, until the calcium content of the productis approximately 20 to 70% of normal and there is secured in the producta calcium to phosphorus ratio of about 0.15 to 0.75, thereby raising thepH of the product, and treating the resulting product with a cationexchange material operating in the hydrogen cycle until the pH of theoriginal milk product is substantially restored, adding an amount ofbutterfat or butterfat-containing material to the treated productsufficient to give the desired fat content in the dried cream, but notto increase the calcium to phosphorus ratio beyond the range of about0.25 to 0.90, condensing and homogenizing the mixture and drying it.

18. A process for producing a dry cream comprising treating skim milkand like milk products having a substantially normal calcium andphosphorus content and a pH of about 6.5 to 6.8 with a cation exchangematerial operating in the sodium cycle, until the calcium content of theproduct is approximately 20 to 70% of normal and there is secured in theproduct a calcium to phosphorus ratio of about 0.15 to 0.75, adding anamount of butterfat or butterfat-containing material to the treatedproduct suflicent to give the. desired fat content in the dried cream,but not to increase the calcium to phosphorus ratio beyond the range ofabout 0.25 to 0.90, condensing and homogenizing the mixture and dryingit.

19. A process for producing a cream product comprising treating skimmilk and like milk products having a substantially normal calcium andphosphorus content and a pH of about 6.5 to 6.8 with a cation exchangematerial operating in the sodium cycle, until the calcium content of theproduct is approximately 20 to 70% of normal and there is secured in theproduct a calcium to phosphorus ratio of about 0.15 to 0.75, adding anamount of butterfat or butterfat-containing material to the treatedproduct suflicient to give the desired fat content in the cream, but notto increase the calcium to phosphorus ratio beyond the range of about0.25 to 0.90, and condensing and homogenizing the mixture.

20. A process for producing a cream product comprising treating skimmilk and like milk products having a substantially norma1 calcium andphosphorus content and a pH of about 6.5 to 6.8 with a cation exchangematerial operating in the sodium cycle, until the calcium content of theproduct is approximately 20 to 70% of'normal and there is secured in theproduct a calcium to phosphorus ratio of about 0.15 to 0.75, therebyraising the pH of the product, and treating the resulting product with acation exchange material operating in the hydrogen cycle until the pH ofthe original milk product is substantially restored, adding an amount ofbutterfat or butterfat-containing materia1 to the treated productsuilicient to give the desired fat content in the .cream, but not toincrease the calcium to phos- 21. A process for producing a milk materiacomprising treating a fluid milk product having a substantially normalcalcium and phosphorus content and a pH of about 6.5 to 6.8 with acation exchange material operating in the sodium cycle, until thecalcium content of the product is approximately 20 to 70% of normal andthere is secured in the product a calcium to phosphorus ratio of about0.15 to 0.75, thereby raising the pH of the product, and treating theresulting product with 'a cation exchange material operating in thehydrogen cycle until the pH of the original milk product issubstantially restored, and drying the treated product.

22. A dry cream product comprising a homogeneous mixture of butterfatand cation-exchanged milk solids not fat having a content of calciumapproximately 20 to 70% of normal and having a calcium to phosphorusratio ranging from about 0.25 to 0.90.

23. A dry cream product comprising a homogeneous mixture of butterfatand cation-exchanged milk solids not fat having a content of calciumapproximately 20 to 45% of norm-a1 and having a calcium to phosphorusratio ranging from about 0.25 to 0.55.

24. A cream product comprising a homogeneous mixture of butterfat andcondensed fluid, cation-exchanged milk solids not fat having a contentof calcium approximately 20 to 70% of norm-a1 and having a calcium tophosphorus ratio ranging from about 0.25 to 0.90.

25. A cream product comprising a homogeneous mixture of butterfat andcondensed fluid, cation-exchanged milk solids not fat having a contentof calcium approximately 20 to 45% of normal and having a calcium tophosphorus ratio ranging from about 0.25 to 0.55.

26. A dry cream product comprising a homogeneous mixture of butterfatand milk solids not fat having a content of calcium approximately 20 to70% of normal and having a calcium to phosphorus ratio ranging fromabout 0.25 to 0.90.

27. A dry cream product comprising a homogeneous mixture of butterfatand milk solids not fat having a content of calcium approximately 20 to45% of normal and having a calcium to phosphorus ratio ranging fromabout 0.25 to 0.55.

LEWIS H. CHRYSLER. EMORY F. ALMY.

REFERENCES CITED The following references are of record in the file ofthis patent:

change treatment, published Ind. and Eng. Chemistry, Nov. 1933, pp.1297-1298.

Journal of Dairy Science, vol. XXX; No. 10, October 1947, pages 737 to746.

Certificate of Correction April 11, 1950 Patent No. 2,503,866

LEWIS H. CHRYSLER ET AL. It is hereby certified that errors appear intheprinted specification of the above numbered patent requiring correctionas follows:

read dryer; co

Column 7, line 42, for driyer 6.0 line 16, for temperature at readtemperature of; line 65, for treat read treated; column 9, line 45, forparticullarly read particularly; column 15, line 71, for 0.14" read0.15; column 17, line 36, for sufiicen read sufiicient; and that thesaid Letters Patent should be read with these corrections therein thatthe same may conform to the record of the case in the Patent Office.

Signed and sealled this 18th day of July, A. D. 1950.

lumn 8, line 13, for 6.0 read i Jon E. DANIELS,

Assistant Commissioner of Patents.

1. A PROCESS FOR PRODUCING A MILK MATERIAL COMPRISING TREATING A FLUIDPRODUCT HAVING A SUBSTANTIALLY NORMAL CALCIUM AND PHOSPHORUS CONTENT ANDA PH OF ABOUT 6.5-6.8 WITH A CATION EXCHANGE MATERIAL OPERATING IN THESODIUM CYCLE, UNTIL THE CALCIUM CONTENT OF THE PRODUCT IS APPROXIMATELY20 TO 70% OF NORMAL AND THERE IS SECURED IN THE PRODUCT A CALCIUM TOPHOSPHORUS RATIO OF ABOUT 0.15 TO 0.75, THEREBY RAISING THE PH OF THEPRODUCT, AND TREATING THE RESULTING PRODUCT WITH A CATION EXCHANGEMATERIAL OPERATING IN THE HYDROGEN CYCLE UNTIL THE PH OF THE ORIGINALMILK PRODUCT IS SUBSTANTIALLY RESTORED.